In the mass production of items such as motor vehicles, manufacturing tolerances exist and in the final assembly of, for example, car doors, the sum of all the relevant tolerances can lead to small inaccuracies in the positioning of the door latch for satisfactory door operation. It is important that the striker plate, which is fitted on the fixed part of the vehicle body is in the correct position relative to the latch, which is fitted to the door edge.
It is customary to provide some degree of adjustability of either the latch or the striker plate so that the two can be correctly set relative to one another during final assembly. It is known to use a jig which fits between the edge of the door and the door pillar and which will set the position of the latch members correctly relative to one another. Such jigs however are awkward to use and are relatively delicate. If they are not handled carefully, they can easily themselves go out of alignment and become worse than useless.
It is normal practice for all the striker plates on a mass production line to be set at a mean position which has been determined as being in the centre of the range of tolerances. During vehicle inspection it is found that this is satisfactory for the majority of vehicles, but that a few vehicles still require to have the striker plates manually adjusted to achieve the correct closing effort. This is labor intensive and requires skilled operatives.